OVERHEAD MONORAIL - THE FUTURE OF TRANSITOverhead monorails has emerged as the future of transit including Innotrans displays ranging from Siemens' rendition of their transit pods to the vehicle display of SW Technologies monorail unibus. Others investing in this future are Skytran (Israel), TransitX (USA), and Terretrane (USA).

Well-planned overhead-monorail infrastructure will bring in an era of low-cost, low-emission, and fast transit. Both high speed rail (HSR) and highways suffer from high infrastructure and maintenance costs; and there is little hope of a self-funded path forward that would free society from this vicious cycle.

SW Technologies cites costs of $7 to $10 million per kilometer (mil/km) for their urban transit system as compared to $10 mil/km for much slower cableways or trams (HSR is best case $30 million per mile with elevated track at over $200 million per mile). With operational vehicles on a test track in Belarus, SW Technologies is poised to implement the first of these Urban transit systems. Terreplane's Designed-to-Evolve approach will bring system costs to $3.5-$5 million per kilometer.

Low cost, easy routing, and low impact/footprint are the drivers. In cities, the footprint of a new system is the bare minimum of station platforms with support towers placed over those platforms. Suspended monorail systems would traverse 1 to 5 km between stations. Unlike cableway systems where vehicles are attached to moving cables; these overhead monorail systems have vehicles moving along stationary monorails or cables.

Overhead monorail transit is a needed step forward in transportation, but greater things are possible and are needed. These systems may resemble older systems (see 1982 Mud Island [overhead] Monorail), but they are quite different with far greater up-side potential.

TERRETRANE'S DESIGNED TO EVOLVE APPROACHTerretrane's technology is based on the overhead monorail systems of SW Technologies, Skytran, and TransitX as being the beginning. For that great future to be realized, these overhead monorail systems must include:

Evolution to smaller and lower-cost guideways (requiring easy and low-cost ability to upgrade (switch out) the monorail guideways of these systems while keeping core infrastructure of towers, station platforms, and support cables connecting the towers at 1 km - 5 km spacing).

Evolution to linear induction motor (LIM) propulsion.

Evolution to partial and then full aerodynamic lift of vehicles beyond certain lower velocities.

Smaller guideway infrastructures are key to lower costs, as low as $4 million per kilometer (less than half of cableways and trams). Lighter-weight vehicles are critical to use smaller guideways, and LIM propulsion is needed for lighter vehicles since these vehicles will not have the weight needed for wheel traction/friction to attain higher speeds. Once freed from the link between weight and traction correlation, further advantages of reduced track stress and track movement are realized by using aerodynamic lift to support the weight of the vehicle.

And so, why has LIM Propulsion fallen to the wayside as more of a token and niche propulsion system rather than emerging as the prominent system. Two thoughts tend to dominate rationale for the stagnant nature of LIM propulsion:

SW Technology's Anatoli Yunitski suggests that 10 mm clearances of these systems reduced the motor efficiency to 50%; and that is high penalty in comparison to rotary motors at efficiencies greater than 90%.

LIM guideways are often confused with short stator guideways; the latter being very expensive tracks of magnet and the former being inexpensive strips or tubes of aluminum.

The second of these is a misconception where even the relatively low cost of aluminum strip reactive rails can be overcome with overhead monorail systems when the reactive rails (armatures) of the linear motors are used as power transmission lines to provide grid power to the vehicle. This is possible for overhead monorails while not possible on the ground (for safety reasons).

LINEAR MOTOR PATH FORWARDFor overhead monorail systems, constant cross section areas ( +- < 0.5 mm deviations) of the monorail/cable would allow pairs of stator electromagnets to operate on opposite sides if the rail. The paired stators double the force to avoid contact of the stator with the armature Lower dimensional deviations and paired stators would readily allow 10 mm clearances to be reduced to 5 mm; with 3 mm being attainable with operational experience.

Substantial to full dampening of the short stator from vehicle weight and disturbances when the vehicle weight is supported by aerodynamic lift where vehicle flaps and dampened connections address vehicle disturbances.

Combined, these two can reduce clearances to 2 mm. Advanced sensing and control technology can further reduce clearances to 1 mm.

Terreplane Technologies brings forth the solution to a stagnant LIM industry and opens up an incredible path of evolution in transit and mankind.

DOUBLE RAIL RIDERSHIPTerretrane will not replace HSR. Initially, the best applications of Terretrane are superport urban transit systems designed to significantly improve access to rail and air ports in cities and extended city regions. This will result in a doubling of HSR ridership in a few years since access is a key limiting factor on rail ridership. Superports improve access to both rail and air transit.

Upon establishing Terretrane superports, the path forward is one for evolution for rail and air transit alike. There is a future for HSR that first includes substantial increases in ridership followed by new tracks of evolution where current versions of trains will slowly evolve in ways yet to be determined.

SINCE MUD ISLANDThe two vehicles of the Mud Island Monorail are connected to a cable that shuttles them back and forth on a horizontal monorail (it is a horizontal cableway); a system with low capacity and little upside potential. The new overhead monorail systems (SW Technologies, Terreplane ...) have stationary cables. A number of advances have expanded the upside potential of overhead monorail systems since Mud Island; these include:

SW Technologies steel wire beams and other approaches to reduce costs; and

Terreplane Technologies with advances in:

a) Linear motor manufacturing (injection molding and self-assembly), b) Designed-to-Evolve approach to reduce the time of introducing new technology from decades to months, and c) Synergy of overhead monorail with linear motor leading to lower clearances and use of same rail for power distribution and armature of linear motor.